Examine source code of Cool

{
  "name": "Cool",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "Untitled design.png"
    },
    "colors": {
      "frame": "rgba(46, 46, 46, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(23, 23, 23, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 0, 0, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(47, 69, 168, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{98ce15f9-a735-45f1-898c-b2a8140e7fe1}"
    }
  }
}